Above are the images of three maps, all representing a cartographical image of the Arab Peninsula, Red Sea, Arab Sea, Persian Gulf and parts of Iran and Iraq. The map on the left is a modern day rendition from the Perry Castenada collection and the two to the right are from 16th century woodcuts that were redrawn versions, from Ptolemy's Geography, which dates to about 150 AD. Ptolemy's maps no longer exist in the original form, and were probably copied from even more ancient maps.
The map at the lower right is "Arabia Felix." From Laurent Fries/Michael Servetus' Geographia. Lyons: Michael & Gaspar Trechsel, -1535. The map at the upper right is claimed to be from Ptolemy's Geographia. Basel: Henric Petri, 1552. There are certain differences that lead me to believe the Petri map was annotated with updated geographical information, which became available from maritime travelers to the area, after the Fries map was drawn. The Freis map likely reflects more of the original Ptolemy. It is obvious; both maps are derived from the same source. Neither map looks anything like the Arab Peninsula as we know it today, however, other than in some general way and it easy to dismiss the original cartographer as sloppy, or unskilled or uneducated. However, that is an assumption that is dangerous to make, in my opinion.
A larger version of the map on the left can be viewed here.
The two maps on the right are courtesy of the Philadelphia Print Shop limited.
First, lets analyze some differences between the two medieval maps on the right with what we see on the current map. On the Freis map there are many large islands shown in the Red sea, but on the Petri map these islands are fewer and smaller. There are a few small islands in the Red Sea. Both old maps show a promontory point of land at the mouth of the Red Sea, though in reality, none exists. The Petri map retains the errant promontory point, and adds another where the Somali Peninsula exists. The Petri map has moved the Y shaped mountain range shown in the Fries map from the Oman Peninsula to the Somali Peninsula. On the East Coast of the Red Sea, neither of the old maps show the ranges of mountains which exist there and show intermittent mountains on the West Coast, although they are almost continuous.
Along the south coast of the Arab Peninsula, where Yemen is today, the Freis map shows many rivers emptying into the Arabic Sea. Those rivers are not really there and they are eliminated on the Petri map. Both old maps show a large promontory about half way along the southern coast of the Arab Peninsula. It does not really exist and neither does the large island to the southwest, nor does the bay with islands exist to the east where the entrance to the Persian Gulf begins.
There is no Peninsula extending from Iran to create the narrow channel entrance into the Persian Gulf, as shown on both old maps and the promontory shown along the southern coast of Pakistan does not exist. The Strait of Hormuz into the Persian Gulf looks nothing like what is shown on the old maps. In fact, the Strait of Hormuz is between a promontory on the southern side, into a bay on the northern side. The mountainous regions on the southern coast of Iran are shown far inland on the old maps, but in reality extend to the coast of the Gulf. The Freis map shows many rivers emptying into the Gulf from the Iran side, but no such rivers exist there. The rivers have been removed in the Petri map, and moved to the north where they still dont exist. The Y shaped mountain range on the Freis map on what can be supposed as the Oman Peninsula does not exist. In fact the Petri map moved those mountains to Somalia, as mentioned previously.
On the Arabia Peninsula, a very prominent range of L shaped mountains is shown on both maps. They do not exist. The very obvious peninsular of Qatar is omitted from both old maps on the northern gulf coast. Instead, both old maps show a mountain range extending to the west on what is now the border between Saudi Arabia and Iraq. This mountain range, simply does not exist. In fact, neither of the old maps looks the least bit like the area in question, and prominent geographical landmarks are shown that arent there, or are there and not shown. One can only conclude that the original cartographer was an idiot, or was mapping a completely different area of the globe and subsequent copiers of the map had made some assumptions in good faith but nevertheless, turned it around somehow.